Treatment of skin with lasers have been the subject of study since the early 1960s. A variety of lasers have been used in dermatologic practice. Different lasers are primarily distinguished by the wavelength of the light produced, measured in nanometers, such as the XeF excimer (351 nm), argon (488 nm, 514 nm), ruby (694 nm), Nd:YAG(1060 nm), and CO.sub.2 (10,600 nm) lasers.
More recently, photothermolysis of skin has been demonstrated using xenon fluoride (XeF) laser pulses and Q-switched ruby laser pulses. It has been found that radiation from Q-switched ruby lasers deeply penetrates the epidermis. It has also been found that application of ruby red laser energy can cause depigmentation of the skin as well as significant follicular damage to the extent that the hair will fall out.
Up to now, the Q-switched ruby laser has been used for the treatment of tattoos and conventional ruby lasers have been used to treat epidermal and dermal pigmented lesions. Studies based on experimentation with Q-switched ruby lasers, as well as other lasers, have reported skin depigmentation and temporary hair loss. Two particular studies titled "Pigmented Guinea Pig Skin Irradiated With Q-switched Ruby Laser Pulses", Arch Dermatol, 125:43-49, 1989 and "Effect of Wavelength on Cutaneous Pigment Using Pulsed Irradiation", J Invest Dermatol, 92:717-720, 1989, teach depigmentation generally and discuss hair regrowth, but do not deal specifically with permanent substantial hair removal. The intent of these studies was not to damage the follicle or the papilla such that the hair would be subject to a disruption of the normal growing cycle over an extended period of time or permanently destroyed.